1. Field of the Invention
The invention concerns a method for making ready-to-use ball game strings in particular for tennis racquets, whereby the string in order to be conditioned for stringing is mounted under tension on a spool where its tension is kept at least essentially constant.
2. Discussion of the Prior Art
A procedure of this kind is known from the document WO-A1-86/02850. The untreated string is taken off under tension from a supply drum braked by a defined torque and is wound at that tension, which generates an elongation in it of 5 to 15% to the length required for stringing, upon the spool.
When the string conditioned by prestressing is taken off the spool to string up in particular a tennis racquet without further delay, the hardness of the stringing drops less in time than if the string had been left unconditioned. Good results are achieved by the procedure described in the document WO-A1-86/02850.
Nevertheless it has been observed that the magnitude of prestressing carried out by the procedure of the said document WO-A1-02850 does vary over the length of the string being wound on the spool. Illustratively when starting the motion of the take-up spool, the tension will increase, and thereby the elongation of the string, over a significant time interval, from an initial zero value to a maximum; thus the tension is not constant during this time interval. Similar considerations apply to the stopping action at the end of spool winding. Moreover tensioned strings undergo creep and the string elongation is further dependent on the rate of winding. Elongation-stabilization would require winding as slowly as possible. However the start-up and stop time intervals with their uneven elongations would be lengthened thereby.